TT Fan Motor Issues Lead to Engine Overheating Problems

I had a similar issue with my 2017 Audi A5 last summer. Having worked on basic car maintenance, I have some experience with cooling system problems. The symptoms were exactly as you describe, engine overheating, especially in traffic, and a non-functioning electric fan motor. After checking the fan motor myself, I took it to a workshop where they diagnosed a faulty wiring connection between the fan motor and its control module. The repair involved replacing damaged wiring and a corroded plug connector. Total cost was 95 Euro including parts and labor. The engine cooling system has worked perfectly since then. Before jumping to conclusions about the electric fan, it would help to know: Does your coolant level show normal? Have you noticed any coolant leaks under the car? Does the fan clutch engage at all when the engine is warm? Are there any warning lights on the dashboard? These details would help determine if its purely an electric fan issue or if there might be other engine cooling components involved. The fan motor problems often start with intermittent operation before complete failure.

Last service was completed at 75000 KM and included a full cooling system check. Thanks for the detailed response. You raise good questions about the radiator fan system. The coolant level is normal and there are no visible leaks. I have not seen any warning lights on the dash. The fan does not engage at all, even after running the engine for 15 minutes at operating temperature. I checked the fuse for the cooling fan and it looks good. It seems like your diagnosis of a potential wiring issue could be spot on, especially since the problems started suddenly. Will get the electrical connections checked first before replacing any major parts.

Yes, those symptoms definitely match what I experienced with my A5. Since you mention the fan doesnt engage even after running at operating temperature, this strengthens my suspicion about the wiring connection to the radiator fan. In my case, the mechanic found corrosion had built up where the wiring harness connects to the electric fan motor. The connection was getting worse over time until the fan stopped working completely. The vehicle overheating happened quite suddenly, just like yours. Since your coolant level is good and there are no leaks, focusing on the electric fan circuit makes sense. A proper diagnosis should include testing the fan motor directly with a power source to confirm if its the motor or the wiring causing the issue. When they did this on my car, the fan motor worked fine when connected directly, proving the wiring was the culprit. The cooling system check during your recent service should rule out most other potential causes. Based on the matching symptoms and your confirmation about the fan not engaging, I would bet you are dealing with the same electrical issue I had.

Thanks for providing those details about your experience with fan wiring issues. The lack of warning lights and normal coolant levels in my TT point to an electrical problem rather than a major cooling system failure. Your repair cost of 95 Euro seems reasonable compared to what I feared might be needed. Good to know the fix could be as simple as replacing corroded wiring and connectors. The sudden onset of my vehicle overheating matches your experience perfectly. I will have the shop test the electric motor fan with a direct power source first, as you suggested. This should quickly show if its a wiring problem or the fan motor itself. Will make sure they check all the connection points for corrosion, especially where the harness meets the fan assembly. Really helpful to hear from someone who had such a similar radiator fan issue. This gives me a much clearer picture of what to expect at the repair shop. Will update once I get it diagnosed and fixed.